This invention relates generally to glass composition and relates, more particularly, to a glass composition suitable for use in glass-to-metal seal applications.
In many seal applications, such as the construction of an electrical feedthrough involving glass-to-metal contact, the glass-to-metal seal must be vacuum-tight to maintain an effective separation between ambient and high vacuum conditions. However, the effectiveness of the seal could be jeopardized if the glass does not possess a high degree of chemical durability and a coefficient of thermal expansion which is high enough to match that of the metal with which the glass is used.
It is, accordingly, an object of the present invention to provide a new and improved glass composition for use in glass-to-metal seal applications which possesses both a high degree of chemical durability and a relatively high coefficient of thermal expansion, a method of making the glass, and a method for forming a glass-to-metal seal.